Solar PV is seen as the leading technology in bringing electricity to Africa, a continent where over 600-million people do not have access to it. There are numerous programs for the rollout of solar PV on the continent, but the adoption of solar in Africa is being hampered by counterfeit and poor-quality panels finding their way into the consumer market.
This was highlighted by a recent report that a shipment of 60 t of “end of life” PV panels, sent for recycling in Italy, had been “relabelled” and smuggled into Africa [1]. The range of bad PV extends from relabelled second-hand panels to low quality and fake panels.
The irony of this is that most of these panels are appearing in the consumer market, which affects individuals who have the means to install their own systems. The appearance of low quality and under-performing panels – as well as outright fake panels – appears to be rife in East and Central Africa [2, 4]. These panels are suspected of being sourced from China, Indonesia, India, Dubai, Taiwan, Thailand, South Africa, and Nigeria [3].
Counterfeit panels
A counterfeit panel is one which is not what it appears to be, generally because of counterfeit labels, which contain counterfeit names, false compliance to testing standards, incorrect panel ratings, and other misleading information. The worst cases encountered show a false panel rating. For example, one panel rated at 300 W had an actual capacity of about 160 W, determined from the physical size of the panel and the condition of the wafers (Figure 1).
Counterfeit products could also be manufacturing rejects, i.e. panels which failed the final test and were sold as “seconds”. Others are second-hand panels which have reached the end of their useful commercial life; while still others are newly manufactured panels of poor quality sold under false brand names. Rejects often show manufacturing defects such as delamination (see Figure 2), and “snail tracks” which indicate cracks in the cell (Figure 3).
Second-hand panels
There is an ongoing problem with second-hand panels finding their way into African markets. Commercial panels are seen to have reached the end of their useful life when the output has fallen to 80% of its initial value. This occurs after a long period in service. The problem is that these panels still produce a useful output, and this is seen by some as qualifying them as good for use “in Africa” where they can function in small home solar systems. Second-hand panels frequently find their way into aid programmes operating in Africa, and although this is a worthy application, it sets the precedent that second-hand is acceptable for African markets.
One problem with second-hand panels is that they have a short remaining operating life. In addition to a reduced output, used panels often exhibit failures such as delamination, discolouration of encapsulant, wafer cracking, deterioration of backing, vapour penetration, corrosion, etc., due to long periods of service under harsh conditions.
Poor quality panels
One of the advantages of solar PV technology is that its modularity allows modules to be made at virtually any size and rated power. Most PV modules sold into the consumer market in Africa are for small residential (e.g. rooftop) systems between 5 and 150 W, whereas a full-sized commercial module typically produces 300 W or more.
This is significant because world-leading companies (OEMs) have focused on optimising their products for large arrays of full-sized modules for large scale utility projects in the developed world and in Africa. This has created an opportunity for smaller OEMs (with potentially lower quality standards) to create smaller modules for developing world consumer markets [2].
Low grade panels are made from low grade PV cells, and are often badly constructed, with mismatched modules and a mix of modules of different sizes and quality. These panels are constructed using wafers which might have been rejected by top-quality manufacturers.
Despite attempts at perfection, the mass production of wafers produces rejects and manufacturers reject broken and defective cells during module production. The defect rate is estimated at 1 to 2% [2]. With a worldwide production of 130 GW in 2019, this means at least 1,3 GW of substandard modules could find their way into the lower grade market.
There is nothing wrong with fabricating a module from reworked cells when it is done properly. Defective areas can be cut away and the remaining good cell fragments can be used. Making modules with smaller cell fragments is often done deliberately to achieve a higher output voltage in small form-factor modules and can be done with minimal impact to product quality. To control the use of substandard modules the industry has established a system of grading [3].
- Grade A: Cells without any visible defects, and the electrical data are within specifications.
- Grade B: These cells have visible but small defects, and the electrical data are within specification. Defects include slight bending, colour deviation, water marks, scratches, paste leakage, and busbar parts missing. Grade B cells are cheaper than Grade A panels and are candidates for use in the counterfeit market.
- Grade C: Cells with defects such a broken pieces and others which reduce the output of the module. The cell can be recut to a smaller size for small panels if done properly. They find application in small gadgets such as garden lighting, domestic floodlights, etc. They are difficult to use in panels as all cells must be the same size.
- Grade D: Cells having multiple defects. Usually, multiple cracks make the wafer unusable.
In addition to module faults, damage and faults may occur during the manufacturing process. The following are common:
- Cracking of modules
- Bad soldering joints
- Delamination of encapsulant and backsheet
These faults may not affect the electrical performance of a new panel but will shorten its life.
Fake panels [5]
Fake panels contain elements which are not PV material, but have been added to increase the size of the panel, to create the impression that the capacity is larger than it is, or to hide defects in the modules. Inclusions are generally paper or board with images of PV cells printed on them. The difference can generally be clearly seen, but it is sometimes artfully done and may be difficult to detect.
Several affected countries have set up industry and government control bodies in an attempt to prevent substandard solar products from reaching the market. As part of this programme, a visual inspection guide [6] has been produced which can be used by purchasers to identify suspect panels [7].
References
[1] E Bellini: “Italian PV panels sent for recycling were instead smuggled to Syria and Africa”, PV Magazine, February 2020.
[2] M Sinclair and K Dew: “Fake and defective PV products circulating in high demand areas” ESI Africa, December 2017.
[3] D de Rooij: “Solar cell grading A-B-C-D”, Sinovoltaics.com
[4] Staffwriter: “How to detect fake solar panels”, Plexus energy blog, July 2018.
[5] Staffwriter: “Experts raise alarm over influx of substandard Chinese solar panels in Africa”, Alternative Africa, August 2019.
[6] R Goodier: “A Visual Inspection Guide to Detect Faulty Solar Products”, Engineeringforchange.com, September 2017.
First published: Energize (NowMedia). Read original article.